NTSB Identification: CHI82DA341
14 CFR Part 91: General Aviation
Accident occurred Monday, September 06, 1982 in PONTIAC, MI
Probable Cause Approval Date: 09/06/1983
Aircraft: AERO COMMANDER 681, registration: N10TN
Injuries: 3 Uninjured.

DURING CRUISE FLIGHT THE PILOT OBSERVED THE HYDRAULIC SYSTEM PRESSURE FLUCTUATING. THE PILOT IMMEDIATELY WENT INTO A HOLD PATTERN AND ATTEMPTED TO ASCERTAIN THE PROBLEM. AFTER REPEATED ATTEMPTS THE PILOT WAS ABLE TO LOWER THE NOSE GEAR AND THE RIGHT MAIN GEAR. DURING FINAL APPROACH FOR THE EMERGENCY LANDING THE PILOT FEATHERED THE LEFT ENGINE AND ON TOUCHDOWN THE RIGHT ENGINE WAS FEATHERED. TOUCHDOWN WAS MADE ON THE RIGHT GEAR WITH FULL RIGHT AILERON. THE PILOT LOST AILERON LIFT AND THE AIRCRAFT SETTLED ONTO THE LEFT GEAR AND THE GEAR COLLAPSED. INVESTIGATION REVEALED THAT THE LEFT, MAIN GEAR HYDRAULIC SYSTEM PLUMBING HAD A FATIGUE HAIRLINE CRACK IN THE PRESSURE LINE LEADING FROM THE PUMP TO THE CYLINDER. THE FRACTURE WAS IN THE 90 DEGREE BEND OF THE LINE.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

HYDRAULIC SYSTEM,LINE..CRACKED

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

HYDRAULIC SYSTEM,LINE..FATIGUE

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

GEAR EXTENSION..NOT POSSIBLE..PILOT IN COMMAND


Contributing Factors

EMERGENCY PROCEDURE..PERFORMED..PILOT IN COMMAND


Contributing Factors

LANDING GEAR,MAIN GEAR..UNLOCKED


Contributing Factors

LANDING GEAR,MAIN GEAR..BUCKLED

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